Blue Heron takes flight at Rockefeller Chapel

There are many excellent early music ensembles in Chicago, but it’s always a welcome occasion to hear top visiting groups as well.

The Boston-based choir Blue Heron performed Friday night at Rockefeller Chapel in the University of Chicago Presents series. The brief yet rewarding program was titled, “A Mass for St. Augustine.”

Blue Heron is engaged in a multiyear project performing and recording music from the “Henrican” partbooks at Peterhouse, Cambridge, and it is from these rather obscure scores that the evening’s selections were drawn.

The 13-member choir, conducted by artistic director Scott Metcalfe, showed themselves a first-class ensemble. Their corporate sound is more robust than many early music groups yet refined and well blended. Blue Heron appears to be a true consortium of soloists and Metcalfe allowed the singers’ individual timbres to shine forth throughout the part writing.

The main work was a mass by that most prolific of early composers, Anonymous. The “Missa sine nomine” (mass without a name) is an attractive work with distinctive harmonic touches and many beautiful passages. The Credo is especially striking with its two- and three-part sections, as is the florid, elaborate polyphony of the concluding Agnus Dei.

Metcalfe led the singers in a refined, scrupulously prepared performance that conveyed the originality of the score. The pure-toned sopranos (here, “trebles”) were especially impressive, with Margot Rood, Sonja Tengblad and Shari Wilson soaring in the stratospheric passages.

The only quibble was one of presentation. The mass was split into two parts with an intermission in the middle—unnecessary when the entire program ran barely an hour and could have been done straight through.

The mass was preceded by Sarum plainchant selections (“Introit: Sacredotes del benedicte” and “Kyrie Orbis factor”), which went with a natural flow and provided a monastic prelude of sorts.

The short program was framed by a pair of Marian votive antiphons. Robert Hunt’s Ave Maria, mater dei led off the evening, and here the singers confidently assayed the restless harmonic contrasts of Hunt’s setting.

More elaborate still was the concluding work, Hugh Aston’s Ave Maria, ancilla trinitatis. A Blue Heron favorite since being performed at their debut concert in 1999, the thirteen subtly varied stanzas of praise for Mary conclude in a remarkably extended and complex Amen. The Blue Heron singers provided superb advocacy, singing with radiant tone and crystal-clear enunciation, and building the melismatic finale to a resplendent coda.